Test the worst input a limit still allows

// before: proves the old attack is blocked
TestOrientation_HugeArray_IsSkipped()

// after: proves the worst accepted input stays cheap
func TestOrientation_WorstAllowed(t *testing.T) {
    img := buildEXIF(offsetsPerTag(2), entriesPerDir(65535)) // max under the cap
    start := time.Now(); _, _ = GetOrientation(img)
    require.Less(t, time.Since(start), time.Second)
}